Understanding the difference between storm surge and flooding

There are two types of inundation that people in Cairns Region need to be aware of storm surge and flooding.

Every property has different risks levels when it comes to a range of natural hazards.

Some properties may be at risk from both storm surge and riverine flooding, some for just one, and others from neither.

Local Disaster Coordinator Rhys Newton said residents needed to understand the different risks that could impact their home or business and plan for what they will do in an emergency.

“In simple terms, Storm Surge is sea water being pushed on shore from the ocean.

“Flooding is fresh water overflowing out of rivers and creeks.” he said.

“Storm surge comes from the sea; it is generated by a cyclone forcing water onshore over a stretch of coastline.

“Flooding occurs when water levels rise above the river, creek banks and drainage systems.

“They are very different types of inundation bringing different risks to different areas.  First step in preparing for disaster is understand your risk.

To understand Storm Surge risk Council has mapped storm surge zones using a colour coded system – the red zone is the highest risk area, closest to the coast, progressing to orange and yellow.

A white zone is considered to be outside the reach of storm surge.

Property near tidal rivers may be included in storm surge zones, even if they are a long way from the coast.

Residents need to be aware which coloured zone they live in and the zone of the house they plan to self-evacuate to.

The easiest method is entering their address in the ‘storm surge search’ feature of Council’s website,  or viewing the storm surge maps on the Cairns Disaster Dashboard.

People with homes and businesses in low-lying areas, close to rivers, creeks, major stormwater drains are most at risk from flooding and can better understand risk by establishing if their property is in a flood area.

Go to Council’s Cairns Disaster Dashboard for more details.

Heavy rains and storms in one area can cause flooding in another community downstream.

When the water levels of local rivers and streams overflow, they can sometimes spill out over large areas.

There are two types of flooding – Riverine and flash:

Flooding in Carins Region can be caused by heavy rainfall and king tide.

Urban drainage overwhelmed by flash flooding is a serious problem and king tide, a natural and predicable tidal cycle, has a noticeable effect where ocean meets land at beaches, estuaries, harbours and other coastal locations.

Understand the risk at your location, develop a plan, pack an emergency kit, listen and watch out and adapt to be safest.

The Bureau of Meteorology issues advice and warnings about potential flooding.

If a flood watch or warning is issued, residents should stay informed by the ABC radio, the Cairns Disaster Dashboard and Cairns Disaster Facebook page.